1. Field of the Invention
The present invention relates to an input/output device and particularly to an input/output device capable of inputting and outputting image data.
2. Description of the Related Art
Conventional input devices include keyboards and such simple mechanisms as mouses, trackballs, touch panels, and tablets. However, these input devices have limitations. For example, keyboards are limited to how compact they can be manufactured and can not be used to input diagrams. Mouses do not allow for easy input of characters and can not be used without a flat surface. Trackballs, also, do not allow for easy input of characters and additionally can not be used for finely detailed input. Both touch panels and tablets ordinarily require a large area to be useful and can not easily be employed in a small input device.
Conventional output devices include liquid crystal display panels and electrophotographic or ink-jet style desktop printers. However, these output devices have limitations. Although desktop electrophotographic and ink-jet printers are being made more and more compact, they are still not very portable. Liquid crystal displays are incapable of producing hard copy.
On the other hand, some stand-alone combination input/output devices have been proposed that are compact and portable. For example, there has been known an image reading head and a printing head both housed in a pillar-shaped housing. The printing head can be used to print an image read by the image reading head. In order to read image data with this portable input/output device, the user grasps the housing casing in hand and moves the device over a medium to be read, or read medium. In order to reproduce the image, the user moves the printing head over a write medium. An encoder is provided to the housing of the input/output device. The encoder contacts the read or write medium and rotates according to the amount that the housing is moved. In this way the amount the housing is moved can be detected.